1. Field of the Invention
The present invention relates to signal processing systems, and more particularly, to a signal processing system for use in an electronic system having a hard disk, a light emitting diode (LED), and a driving circuit for driving the LED to operate and indicate a state of use of the hard disk, so as to process pulse signals generated by the driving circuit and allow the processed pulse signals to drive the LED to glitter at a frequency suitable for a user to perceive.
2. Description of the Prior Art
A system (a computer system or a servo system) generally comprises three major components, namely a central processing unit (CPU), a hard disk, and a memory, which are equally important. The hard disk, the most important extrinsic storage device of the system (as opposed to other auxiliary storage devices, such as floppy disks, CD-ROMs, flash memory, and magnetic tapes), not only serves as the system's hub of data storage, but also stores most of the programs and data required for the system's operation.
In order to enable a system user to identify the current state of use of the system's hard disk (for example, whether or not a hard disk is present, and whether or not the system is accessing the hard disk for data). Systems nowadays employ mostly a driving circuit installed in system hardware architecture to generate, when the system is accessing the system's hard disk, a pulse signal ACTLED_N for driving a LED (a light-emitting diode) to operate and indicate the current state of use of the system's hard disk. For instance, in the event that the system does not have any hard disk, or electrical connection between the hard disk and the system is poor, the LED will not light up, thus informing the user that, for the time being, the system does not have any hard disk, or electrical connection between the hard disk and the system is poor. In the event that the system has a hard disk but the system is not accessing the hard disk for data, the driving circuit will generate a logic high (logic “1”) signal for driving the LED to stay alight, thus informing the user that, for the time being, the system has a hard disk but the hard disk is idle. In the event that the system has a hard disk and is accessing the hard disk for data, the driving circuit will generate the pulse signal ACTLED_N for driving the LED to glitter, thus informing the user that, for the time being, the system is accessing the hard disk for data, that is, the hard disk is currently in use.
Although the aforesaid conventional system has a mechanism for using a LED to indicate a state of use of a hard disk, the quantity of data for which the system accesses the hard disk varies and thus the pulse width of the pulse signal ACTLED_N generated by the driving circuit of the system varies, and in consequence the frequency at which the LED connected to the driving circuit glitters varies. Referring to FIG. 7, the system accesses the hard disk for a small amount of data, the waveform of the pulse signal ACTLED_N generated by the driving circuit is depicted by the waveform of a signal f1 shown in FIG. 7. The signal f1 is a logic low (logic “0”) signal only within duration ΔT1, where the duration ΔT1 accounts for a small part of a period T, and thus the LED is off for a short while. As a result, the user is unable to readily perceive the glitter of the LED in the short duration ΔT1, and thus the user mistakenly thinks that the hard disk fails to respond to the system when the system attempts to access the hard disk. And further, the user mistakenly thinks that there is a hard disk failure, and thus the user starts to perform laborious, time-consuming follow-up jobs, such as testing and repairing the hard disk. Referring to FIG. 7, alternatively, the system accesses the hard disk for a large amount of data, the waveform of the pulse signal ACTLED_N generated by the driving circuit is depicted by the waveform of a signal f2 shown in FIG. 7. The signal f2 is a logic low signal within duration ΔT2, where the duration ΔT2 accounts for a large part of the period T, and thus the LED is off for a long while. As a result, the user mistakenly thinks that the hard disk is absent from the system, or that electrical connection between the hard disk and the system is poor. Similarly, the user may therefore mistakenly think that there is a hard disk failure, and thus the user starts to perform laborious, time-consuming follow-up jobs, such as testing and repairing the hard disk.
In short, a conventional system does not provide users with an efficient mechanism for indicating the state of use of a hard disk. In consequence, users are seldom efficiently and directly informed of the current state of use of a hard disk by means of a LED and thereby are likely to handle the hard disk wrongly, for example, testing the hard disk to see if the hard disk fails or electrically connects to the system poorly.
Accordingly, an issue that faces the industry and needs an urgent solution is related to endeavors-to provide a mechanism for indicating the state of use of a hard disk so as to overcome various drawbacks of the prior art.